Absorbent article having stretchable fastening member

ABSTRACT

An absorbent article comprising a stretchable fastening member is disclosed. The absorbent article comprises a chassis and a stretchable fastening member. The chassis extends longitudinally and laterally and comprises a liquid pervious topsheet, a liquid impervious backsheet and an absorbent core disposed therebetween. The stretchable fastening member comprises a fixed portion permanently joined to the chassis, a distal portion provided with a fastening material and a stretchable panel positioned between the fixed portion and the distal portion. The stretchable fastening member is joined to the chassis such that the distal portion is positioned laterally outwardly from the fixed portion in the flat-out configuration of the stretchable fastening member. The stretchable panel of the stretchable fastening member comprises a first stretchable zone and a second stretchable zone disposed in the lateral direction. The first stretchable zone is capable of providing extensibility upon an initially applied extension force. Extensibility of the second stretchable zone is restricted by a restriction means until the restriction means is inactivated, and the restriction means is inactivated upon a further applied extension force such that the second stretchable zone provides an additional extensibility to reduce a stress developed in the stretchable panel.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/440,919, filed Jan. 17, 2003.

TECHNICAL FIELD

[0002] The present invention relates to an absorbent article comprisinga stretchable fastening member. More specifically, the present inventionrelates to an absorbent article comprising a stretchable fasteningmember comprising a first stretchable zone being capable of providingextensibility upon an initially applied elongation force and a secondstretchable zone to provide an additional extensibility upon a furtherapplied elongation force to reduce a stress developed in the stretchablefastening member.

BACKGROUND

[0003] Fastening systems are widely known and widely used. Disposableabsorbent articles are one example which is provided with fasteningsystems. The fastening systems provided on disposable absorbent articlesare to form a closure of so-called open type absorbent articles (e.g.,taped diaper) when in use or to adjust the dimension of the waistcircumference of so-called pull-on type absorbent articles (e.g.,pull-on diaper). In conventional arrangement of fastening systems ondisposable diapers, the fastening member of the fastening system isprovided to extend in the direction parallel to the lateral direction ofthe diaper such that the fastening member is pulled in the lateraldirection for fastening the diaper and for forming a defined dimensionof the waist opening. This provides a lateral tensioning force to keepthe diaper in the abdominal region of the wearer.

[0004] Fastening members provided with stretchability have been alsowell known and used in absorbent articles such as diapers. The use ofstretchable fastening member allows the diaper to accommodate wideranges of wearer's waist circumference. However, the stress developed inthe stretchable fastening member is very different depending on thecircumference size of the wearer's waist. For example, the stretchablefastening member generates higher stress to cause excess forces on thewearer's body when the diaper having the stretchable fastening member isapplied to a relatively big wearer than when the same diaper is appliedto a relatively small wearer. Such excess forces cause skin problemssuch as red marking. In contrast, the stretchable fastening membergenerates only smaller stress to cause insufficient force on thewearer's body when the diaper is applied to a relatively small wearerthan when the same diaper is applied to a relatively big wearer. Suchinsufficient force causes fitment problems of the diaper such assagging. These problems are due to a typical behavior of theconventional stretchable fastening member in which stress developed inthe stretchable fastening member simply continuously increases as strainof the stretchable fastening member increases.

[0005] European Patent publication EP 0 838 205 A3 published on May 31,2002 discloses a disposable absorbent garment including a pair ofdifferently stretchable ear members. Each differently stretchable earmember comprises a stretchable inner ear portion having a firststretchable characteristic and a stretchable outer ear portion having asecond stretchable characteristic. It is stated that each stretchableouter ear portion preferably has a lower tension than stretchable innerear portions, and each stretchable outer ear portion preferably has anelongation equal to or greater than that of a stretchable inner earportion. Because stretchable inner ear portions are used primarily tofit and support absorbent article on the wearer, stretchable outer earportions may have a lower tension so that they easily stretch to permitsnap fastener to be closed without adding additional tension or stretchto inner ear portions that provide the proper fit and support. Thus, thestretchable inner ear portion and the stretchable outer ear portion maytake a different stress-strain curve. However, the stress developed insuch a stretchable ear member continuously increases as the strain ofthe stretchable ear member increases The stretchable ear member of theart can not reduce the stress developed in the stretchable ear member asit is stretched. Therefore, the stretchable ear member generates higherstress to cause excess forces on the wearer's body when the diaper isapplied to a relatively big wearer. On the contrary, the stretchable earmember only generates stress to cause insufficient force on the wearer'sbody when the diaper is applied to a relatively small wearer. Thus, thestretchable ear member of the art limits the range of wearer's waistcircumference size in which the diaper is comfortably applicable to thewearer.

[0006] Based on the foregoing, there is a need for an absorbent articlehaving a stretchable fastening member being capable of controllingstress over the wide range of strain to accommodate wide ranges ofwearer's waist circumference. None of the existing absorbent articlesprovides all of the advantages and benefits of the present invention.

SUMMARY

[0007] The present invention is directed to an absorbent articlecomprising a stretchable fastening member. The absorbent articlecomprises a chassis and a stretchable fastening member. The chassisextends longitudinally and laterally and comprises a liquid pervioustopsheet, a liquid impervious backsheet and an absorbent core disposedtherebetween. The stretchable fastening member comprises a fixed portionpermanently joined to the chassis, a distal portion provided with afastening material and a stretchable panel positioned between the fixedportion and the distal portion. The stretchable fastening member isjoined to the chassis such that the distal portion is positionedlaterally outwardly from the fixed portion in the flat-out configurationof the stretchable fastening member. The stretchable panel of thestretchable fastening member comprises a first stretchable zone and asecond stretchable zone disposed in the lateral direction. The firststretchable zone is capable of providing extensibility upon an initiallyapplied extension force. Extensibility of the second stretchable zone isrestricted by a restriction means until the restriction means isinactivated, and the restriction means is inactivated upon a furtherapplied extension force such that the second stretchable zone providesan additional extensibility to reduce a stress developed in thestretchable panel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] While the specification concludes with claims particularlypointing out and distinctly claiming the invention, it is believed thatthe present invention will be better understood from the followingdescription of preferred embodiments taken in conjunction with theaccompanying drawings in which:

[0009]FIG. 1 is a top plan view of one embodiment of an absorbentarticle having a stretchable fastening member with a restriction means;

[0010]FIG. 2 is a partially enlarged top plan view of the stretchablefastening member in its flat-out configuration;

[0011]FIG. 3 is a cross-sectional view taken along the line III-III ofFIG. 2;

[0012]FIG. 4 is a cross-sectional view taken along the line III-III ofFIG. 2 in which the first stretchable zone is stretched;

[0013]FIG. 5 is a cross-section view taken along the line III-III ofFIG. 2 in which the restriction means is inactivated and the stretchablefastening member is stretched;

[0014]FIG. 6 is a graph showing the stress-strain curve of thestretchable fastening member shown in FIG. 2;

[0015]FIG. 7 is a first alternative embodiment of the stretchablefastening member with a restriction means;

[0016]FIG. 8 is a graph showing the stress-strain curve of thestretchable fastening member shown in FIG. 7;

[0017]FIG. 9 is a second alternative embodiment of the stretchablefastening member with a restriction means;

[0018]FIG. 10 is a graph showing the stress-strain curve of thestretchable fastening member shown in FIG. 9;

[0019]FIG. 11 is a third alternative embodiment of the stretchablefastening member with a restriction means;

[0020]FIG. 12 is a fourth alternative embodiment of the stretchablefastening member with a restriction means; and

[0021]FIG. 13 is a fifth alternative embodiment of the stretchablefastening member with a restriction means.

DETAILED DESCRIPTION

[0022] As used herein, the term “comprising” means that other steps andother ingredients which do not affect the end result can be added. Thisterm encompasses the terms “consisting of” and “consisting essentiallyof.”

[0023] As used herein, the term “absorbent article” refers to deviceswhich absorb and contain body exudates, and more specifically, refers todevices which are placed against or in proximity to the body of thewearer to absorb and contain the various exudates discharged from thebody. The term “disposable” is used herein to describe absorbentarticles which generally are not intended to be laundered or otherwiserestored or reused as an absorbent article (i.e., they are intended tobe discarded after a single use and, preferably, to be recycled,composted or otherwise disposed of in an environmentally compatiblemanner). As used herein, the term “disposed” is used to mean that anelement(s) of the diaper is formed (joined and positioned) in aparticular place or position as a unitary structure with other elementsof the diaper or as a separate element joined to another element of thediaper. As used herein, the term “joined” encompasses configurationswhereby an element is directly secured to another element by affixingthe element directly to the other element, and configurations whereby anelement is indirectly secured to another element by affixing the elementto intermediate member(s) which in turn are affixed to the otherelement.) As used herein, the term “diaper” refers to an absorbentarticle generally worn by infants and incontinent persons about thelower torso. The present invention is also applicable to other absorbentarticles such as incontinence briefs, incontinence undergarments,absorbent inserts, diaper holders and liners, feminine hygiene garments,and the like. The term “longitudinal”, as used herein, refers to a line,axis or direction in the plane of the absorbent article that isgenerally aligned with (e.g., approximately parallel to) a verticalplane which bisects a standing wearer into left and right body halveswhen the absorbent article is worn. The terms “transverse” or “lateral”used herein, are interchangeable, and refer to a line, axis or directionwhich lies within the plane of the absorbent article that is generallyperpendicular to the longitudinal direction.

[0024]FIG. 1 is a top plan view of the diaper 20 in its flat-outconfiguration. The diaper 20 comprises a chassis 30 and a stretchablefastening member 40. Referring to FIG. 2 showing a partially enlargedtop plan view of the stretchable fastening member in its flat-outconfiguration and FIG. 3 showing a cross-sectional view taken along theline III-III of FIG. 2, the diaper 20 has a wearer facing surface 26, anopposite outer surface 28, a longitudinal centerline L, and a lateralcenterline T. The diaper 20 also has longitudinal side edges 22 whichrun generally in the longitudinal direction of the diaper and lateralend edges 24 which run between the longitudinal side edges 22 generallyin the lateral direction of the diaper 20. The periphery of the diaper20 is defined by the longitudinal side edges 22 and the lateral endedges 24. The diaper 20 further has a front waist region 21, a backwaist region 23 and a crotch region 25 disposed between the front waistregion 21 and the back waist region 23.

[0025] The diaper 20 comprises a chassis 30 and a stretchable fasteningmember 40 joined to the chassis 30. The chassis 30 has a generallyrectangle shape in its flat-out configuration and extends longitudinallyand laterally. The chassis 30 comprises a liquid pervious topsheet 31; aliquid impervious backsheet 32; an absorbent core 33 which is disposedbetween at least a portion of the topsheet 31 and the backsheet 32; anda side flap 39 extending laterally outwardly from the absorbent core 33.The chassis 30 has lateral end edges 34 and longitudinal side edges 35.The lateral end edge 34 of the chassis 30 generally defines the lateralend edge 24 of the diaper 20. The longitudinal side edge 35 of thechassis 30 generally defines the longitudinal side edge 22 of the diaper20. The chassis 30 may further comprise a leg cuff 36 comprising anelasticized gasketing cuff 37 disposed adjacent to the longitudinal sideedge 22 in the crotch region 25 and an elasticized barrier cuff 38. Thechassis 30 may also comprise an elastic waist feature (not shown inFigures).

[0026] The liquid pervious topsheet 31 is preferably positioned adjacentthe body-facing surface of the absorbent core 33 and may be joinedthereto and/or to the backsheet 32 by any attachment means known in theart. The topsheet 31 is preferably compliant, soft feeling, andnon-irritating to the wearer's skin. Further, at least a portion of thetopsheet 31 is liquid pervious, permitting liquid to readily penetratethrough its thickness. A suitable topsheet 31 may be manufactured from awide range of materials, such as porous foams; reticulated foams;apertured plastic films; or woven or nonwoven webs of natural fibers(e.g., wood or cotton fibers), synthetic fibers (e.g., polyester orpolypropylene fibers), or a combination of natural and synthetic fibers.Preferably, the topsheet 31 is made of a hydrophobic material or istreated to be hydrophobic in order to isolate the wearer's skin fromliquids contained in the absorbent core 33. If the topsheet 31 is madeof a hydrophobic material, preferably at least the upper surface of thetopsheet 31 is treated to be hydrophilic so that liquids will transferthrough the topsheet more rapidly.

[0027] The liquid impervious backsheet 32 is generally that portion ofthe diaper 20 positioned adjacent the garment-facing surface of theabsorbent core 33. The backsheet 32 prevents the exudates absorbed andcontained therein from soiling articles that may contact the diaper 20,such as bedsheets and undergarments. In preferred embodiments, thebacksheet 32 is impervious to liquids (e.g., urine) and comprises a thinplastic film. Suitable backsheet materials may include breathablematerials that permit vapors to escape from the diaper 20 while stillpreventing exudates from passing through the backsheet 32. Exemplarybreathable materials may include materials such as woven webs, nonwovenwebs, composite materials such as film-coated nonwoven webs, andmicroporous films. The backsheet 32 may be covered by a woven or anonwoven to impart more cloth-like appearance to the diaper. Preferablya nonwoven is provided to cover the entirety of the backsheet 32.

[0028] The absorbent core 33 may comprise any absorbent material that isgenerally compressible, conformable, non-irritating to the wearer'sskin, and capable of absorbing and retaining liquids such as urine andother certain body exudates. The absorbent core 33 can be manufacturedin a wide variety of sizes and shapes (e.g., rectangular, hourglass,“T”-shaped, asymmetric, etc.) and may comprise a wide variety ofliquid-absorbent materials commonly used in disposable diapers and otherabsorbent articles such as comminuted wood pulp, which is generallyreferred to as airfelt. Examples of other suitable absorbent materialsinclude creped cellulose wadding; meltblown polymers, including coform;chemically stiffened, modified or cross-linked cellulosic fibers;tissue, including tissue wraps and tissue laminates; absorbent foams;absorbent sponges; superabsorbent polymers; absorbent gelling materials;or any other known absorbent material or combinations of materials. Inany case all or a portion of the core may include slits which allow thecore to form openings when stretched into which fecal mater can flow.The configuration and construction of the absorbent core 33 may also bevaried (e.g., the absorbent core(s) or other absorbent structure(s) mayhave varying caliper zones, a hydrophilic gradient, a superabsorbentgradient, or lower average density and lower average basis weightacquisition zones; or may comprise one or more layers or structures).However, the total absorbent capacity of the absorbent core 33 should becompatible with the design loading and the intended use of the diaper20.

[0029] The side flap 39 is a part of the chassis 30 along thelongitudinal side edge 35 of the chassis 30 which extends laterallyoutwardly from the absorbent core 33. The side flap 39 may be formedwith at least one element constituting the chassis 30, such as anextension of topsheet, an extension of backsheet (either of a backsheetfilm or a nonwoven outer cover), an extension of a leg cuff, or acombination thereof. Alternatively, the side flap 39 may be formed witha separate element joined to other elements of the chassis, such as atopsheet, a backsheet, and/or a leg cuff.

[0030] The leg cuff 36 provides improved containment of liquids andother body exudates. The leg cuff 36 may comprise several differentembodiments for reducing the leakage of body exudates in the legregions. Such embodiments are disclosed in, e.g., U.S. Pat. No.4,909,803 issued to Aziz et al. on Mar. 20, 1990; U.S. Pat. No.4,695,278 issued to Lawson on Sep. 22, 1987; U.S. Pat. No. 4,795,454issued to Dragoo on Jan. 3, 1989; and U.S. Pat. No. 4,704,115 issued toBuell on Nov. 3, 1987; each of which are incorporated herein byreference. It is preferred that the leg cuff 36 comprises at least anelasticized barrier cuff 38 such as described in the above-referencedU.S. Pat. No. 4,909,803. The leg cuff 36 also comprises an elasticizedgasketing cuff 37 with one or more elastic strands, positioned outboardof the barrier cuff such as described in the above-referred U.S. Pat.No. 4,695,278.

[0031] The stretchable fastening member 40 is provided on the back waistregion 23 of the diaper 20 and is joined to the chassis 30. Thestretchable fastening member 40 comprises a fixed portion 42, a distalportion 44 and a stretchable panel 46. The fixed portion 42 ispermanently joined to the side flap 39 of the chassis 30 at bondingsites 43 by any known means such as adhesives, heat bonding, pressurebonding, heat and pressure bonding, ultrasonic bonding, or anycombination thereof. The distal portion 44 is provided with a fasteningmaterial 48 used to form a closure of the diaper 20 with a landing zonemember (not shown in the drawings) which is provided on the front waistregion 21 of the diaper 20. The stretchable panel 46 is positionedlaterally between the fixed portion 42 and the distal portion 44. Thestretchable panel 46 provides stretchability upon an applied extensionforce generated by pulling the stretchable fastening member 40. As shownin FIG. 2, the distal portion 44 is positioned laterally outwardly fromthe fixed portion 42 through the stretchable panel 46 in the flat-outconfiguration of the stretchable fastening member 40. The fixed portion42, the distal portion 44 and the stretchable panel 46 may be formedwith an integral material or may be formed with separate materialsjoined to each other. In the embodiment shown in FIGS. 2 and 3, thefixed portion 42 and the distal portion 44 are formed with an extensionof the stretchable panel 46.

[0032] The distal portion 44 of the stretchable fastening member 40 isprovided with a fastening material 48. The fastening material 48 isjoined to the extension of the stretchable panel 46 through anintermediate sheet 50 which may comprise a plastic film. However, thefastening material 48 may be directly joined onto the extension of thestretchable panel 46. The fastening material 48 is joined to theextension of the stretchable panel 46 by any known means. In theembodiment shown in FIGS. 2 and 3, the fastening material 48 is joinedto the intermediate plastic film 50 by adhesives and the intermediateplastic film is joined to the extension of the stretchable panel 46 bypressure and heat bonding means at the bonding sites 52. The fasteningmaterial 48 is intended to provide a fastening means for engaging thelanding zone member so as to provide a secure side closure for thediaper 20. In the embodiment shown in FIGS. 2 and 3, the fasteningmaterial 48 comprises a hook fastening material comprising a pluralityof hooks 54 and the base substrate 56 to support the hooks 54. It shouldbe understood that the use of the term “hook” should be non-limiting inthe sense that the engaging elements may comprise any shapes as areknown in the art so long as they are adapted to engage a complementarylanding zone member. Alternatively, the fastening material 48 may beadhesives or a combination of adhesives and hook fastening materials.

[0033] The stretchable panel 46 may comprise any material exhibitingstretchability including a plastic film, woven, or nonwoven webs ofnatural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g.,polyester or polypropylene fibers), elastomeric adhesives or acombination of natural and synthetic fibers or may comprise anycombination of materials thereof. The stretchable panel 46 is preferablycompliant, soft feeling, and non-irritating to the wearer's skin as thestretchable panel 46 may touch the wearer's skin when in use. Further,at least a portion of the stretchable panel 46 may be vapor pervious,permitting vapor to readily penetrate through its thickness. Suitablestretchable panel materials include a stretchable laminate comprising astretchable plastic film and nonwoven layers laminated on the plasticfilm such that the stretchable plastic film is interposed between thenonwoven layers.

[0034] The stretchable panel 46 extends laterally outwardly from thefixed potion 42 and provides stretchability between the fixed portion 42and the distal portion 44. The stretchable panel 46 is extensible in thelateral direction. The stretchable panel 46 comprises a firststretchable zone 60 and a second stretchable zone 62 which is disposedlaterally inwardly from the first stretchable zone 60. Therefore, thefirst stretchable zone 60 and the second stretchable zone 62 arepositioned adjacent to the distal portion 44 and the fixed portion 42,respectively. The first stretchable zone 60 is capable of providingextensibility upon an initially applied extension force generated bypulling the stretchable fastening member 40. However, extensibility ofthe second stretchable zone 62 is restricted by a restriction means 64until the restriction means 64 is inactivated. Therefore, the only firststretchable zone 60 provides extensibility upon an initially appliedextension force and the extensibility of the second stretchable zone 62is preserved until the restriction means 64 is inactivated (refer toFIG. 4). When the restriction means 64 is inactivated upon a furtherapplied extension force as shown in FIG. 5, the second stretchable zone62 is capable of providing an additional extensibility to reduce astress developed in the stretchable panel 46 (i.e., stress developed inthe first stretchable zone 62). The term “inactivated” used herein meansthat the restriction means loses at least a part of restriction functionso that at least a part of the second stretchable zone is capable ofproviding an extensibility. Therefore, even though the restriction meansis inactivated, the restriction means may still provide a part ofrestriction function while it does not provide a full restrictionfunction as initially installed. The term “full restriction function asinitially installed” means the restriction function of the restrictionmeans which a fresh diaper taken out from a new package exhibits.

[0035]FIG. 6 shows a stress-strain curve of the entire stretchable panel46 combining the first stretchable zone 60 and the second stretchablezone 62. In FIG. 6, the curve S1 exhibits a stress-strain curve of thefirst stretchable zone 60. The curve X exhibits a stress-strain curve ofthe entire stretchable panel 46. The profile difference between thecurve S1 and the curve X is due to the lateral width difference of thematerial which provides stretchability. As shown, the first stretchablezone 60 (curve S1) provides relatively higher stress than the entirestretchable panel 46 (curve X) at low strain zone (e.g., at the strainbetween about 20 mm and about 40 mm) to generate force to sustain thediaper 20 on the wearer. However, the first stretchable zone 60 rapidlyincreases the stress at the high strain zone (e.g., at the strain zonehigher than about 40 mm) to cause excess force on the wearer's skin. Onthe contrary, the entire stretchable panel 46 would provide anappropriate stress at the high strain zone to generate force to sustainthe diaper 20 on the wearer without causing excess force on the wearer'sskin. Therefore, it is desirable to be able to use the first stretchablezone 60 exhibiting the curve S1 at the low strain zone and the entirestretchable panel 46 exhibiting the curve X at the high strain zone.

[0036] In the present invention, the restriction means 64 withstands theinitially applied extension force to restrict the stretchability of thesecond stretchable zone 62 until the restriction means 64 isinactivated. Therefore, the first stretchable zone 60 is stretched alongthe arrow A on the curve S1 upon an initially applied extension forcegenerated by pulling the stretchable fastening member 40 and thestress-strain curve of the stretchable fastening member 40 follows thecurve S1. When the stretchable fastening member 40 is stretched by afurther applied extension force, the restriction means 64 is inactivatedand the second stretchable zone 62 provides an additional extensibilityto reduce the stress developed in the stretchable panel 46 (i.e., thestress developed in the first stretchable zone 60) as shown by the arrowB in FIG. 6. In the embodiment shown in FIG. 6, the restriction means 64is inactivated at the strain of about 40 mm. Then, the entirestretchable panel 46 is stretched along the arrow C on the curve X upona further applied extension force and the stretchable fastening member40 follows the curve X In the embodiment shown in FIG. 6, if the onlyfirst stretchable zone 62 is used for the stretchable fastening member40, the strain range is limited to between about 17 mm and about 40 mmto obtain the stress of between about 150 g/25 mm and about 250 g/25 mm.If the entire stretchable panel 46 is used for the stretchable fasteningmember 40, the strain range is limited to between about 40 mm and about80 mm to obtain the same range. However, the present invention allows toutilize the strain range of between about 17 mm and about 80 mm toobtain the same range. Thus, the stretchable fastening member 40 of thepresent invention provides a relatively constant stress over the widerange of strain to accommodate wide ranges of wearer's waistcircumference without causing skin problems by excess force and saggingproblems by insufficient force. While the restriction means 64 isinactivated by an applied extension force to pull the stretchablefastening member 40, it is obvious that the restriction means 64 may beinactivated by the user of the diaper before application of the diaper20 to the wearer if the diaper is used for a relatively big wearer. Itis preferable that the restriction means 64 is inactivated before thestretchable fastening member 40 generates the stress to cause an excessforce on the wearer's skin. Therefore, the restriction means 64 ispreferably inactivated when the applied extension force is not more than350 g/25 mm. The restriction means 64 is also preferably inactivatedwhen the applied extension force is not less than 150 g/25 mm such thatthe restriction means withstands at least an initially applied extensionforce.

[0037] The restriction means 64 in the embodiment shown in FIGS. 2 and 3comprises a bonding means 66 to detachably join a portion of thestretchable panel 46 to the side flap 39 of the chassis 30. The bondingmeans 66 is provided in the configuration where the stretchable panel 46is unfolded and superposed on the side flap 39. The bonding means 66 isdisposed between the fixed portion 42 and the distal portion 44. Therestriction means 64 shown in FIG. 2 comprises three spots of bondingmeans 66 comprising a waist bonding means, a leg bonding means and acentral bonding means between the waist and leg bonding means such thatthee bonging means align in the longitudinal direction. If desired, thecentral bonding means may be removed in the embodiment shown in FIG. 2.The bonding means 66 virtually divides the stretchable panel 46 at theline connecting the three bonding means 66 to provide the firststretchable zone 60 extending between the distal portion 44 and thebonding means 66 and the second stretchable zone 62 extending betweenthe fixed portion 42 and the bonding means 66. The bonding means 66restricts the majority of stretchability of the second stretchable zone62. Alternatively, the bonding means 66 may comprise four or more ofbonding spots or may comprise a continuous bonding line to furtherrestrict the stretchability of the second stretchable zone 62. The sideflap 39 is preferably less stretchable than the stretchable panel 46,especially than the second stretchable zone 62, in order to restrictextensibility of the second stretchable zone 62. It is furtherpreferable that the side flap 39 is non-stretchable for the samepurpose.

[0038] While the bonding means may be formed with any known materials ormethods such as adhesives, heat bonding, pressure bonding, heat andpressure bonding, ultrasonic bonding, or any combination thereof, thebonding strength of the bonding means 66 is selected so that the bondingmeans 66 withstands an initially applied extension force to maintainjoint of the stretchable panel 46 to the side flap 39, but isinactivated upon a further applied extension force to detach thestretchable panel 46 from the side flap 39. In the embodiment shown inFIGS. 2 and 3, the bonding means 66 is formed by applying heat andpressure. The heat and pressure locally melts the materials of thestretchable panel 46 and the side flap 39 to form a fragile bonding siteas shown in FIG. 3. The bonding strength of the bonding means 66 can beadjusted by changing the temperature and pressure. Alternatively, thebonding means 66 is formed with adhesives and the bonding strength ofthe bonding means can be adjusted by changing the amount of adhesivesused.

[0039] Many alternatives are possible in forming a stretchable fasteningmember of the present invention while only representative examples aredescribed below. FIG. 7 shows an alternative embodiment of a stretchablefastening member 40. The stretchable fastening member 40 shown in FIG. 7comprises two sets of restriction means; first restriction means 70 andsecond restriction means 72. If desired, the stretchable fasteningmember 40 may comprise three or more sets of restriction means disposedin the lateral direction. Each set of restriction means may comprisethree bonding means disposed in the longitudinal direction. Thestretchable panel 46 comprises a first stretchable zone 74, a secondstretchable zone 76 and a third stretchable zone 78. The firstrestriction means 70 virtually divides the stretchable panel 46 into thefirst stretchable zone 74 and the second stretchable zone 76 in thelongitudinal direction. The second restriction means 72 virtuallydivides the stretchable panel 46 into the first stretchable zone 76 andthe second stretchable zone 78 in the longitudinal direction.

[0040]FIG. 8 shows a stress-strain curve of the entire stretchable panel46 combining the first stretchable zone 74, the second stretchable zone76 and the third stretchable zone 78. In FIG. 8, the curve S1 exhibits astress-strain curve of the first stretchable zone 74. The curve S2exhibits a stress-strain curve of a combined zone of the firststretchable zone 74 and the second stretchable zone 76. The curve Xexhibits a stress-strain curve of the entire stretchable panel 46. Thefirst restriction means 70 withstands the initially applied extensionforce to restrict the stretchability of the second stretchable zone 62and the third stretchable zone 78 until the first restriction means 70is inactivated. Therefore, the first stretchable zone 74 is stretchedalong the arrow A on the curve S1 upon an initially applied extensionforce generated by pulling the stretchable fastening member 40 and thestress-strain curve of the stretchable fastening member 40 follows thecurve S1. When the stretchable fastening member 40 is stretched by afurther applied extension force, the first restriction means 70 isinactivated and the second stretchable zone 76 provides an additionalextensibility to reduce the stress developed in the stretchable panel 46(i.e., the stress developed in the first stretchable zone 74) as shownby the arrow B in FIG. 8. Then, the combined zone of the firststretchable zone 74 and the second stretchable zone 76 is stretchedalong the arrow C on the curve S2 upon a further applied elongation andthe stretchable fastening member 40 follows the curve S2. The secondrestriction means 72 withstands the further applied extension force torestrict the stretchability of the third stretchable zone 78. When thestretchable fastening member 40 is stretched by a further appliedextension force, the second restriction means 72 is inactivated and thethird stretchable zone 78 provides an additional extensibility to reducethe stress developed in the stretchable panel 46 as shown by the arrow Din FIG. 8. Then, the entire stretchable panel 46 is stretched along thearrow E on the curve X upon a further applied extension force and thestretchable fastening member 40 follows the curve X.

[0041]FIG. 9 also shows an alternative embodiment of a stretchablefastening member 40. The stretchable fastening member 40 shown in FIG. 9comprises a restriction means comprising a waist restriction means 80and a leg restriction means 82. The restriction means 80 and 82 maycomprise a bonding means disposed generally in the longitudinaldirection. The stretchable panel 46 comprises a first stretchable zone84 and a second stretchable zone 86. The restriction means 80 and 82virtually divides the stretchable panel 46 into the first stretchablezone 84 and the second stretchable zone 86 at a line connecting therestriction means 80 and 82. The bonding strength of the waistrestriction means is different from the bonding strength of the legrestriction means. In the embodiment shown in FIG. 9, the bonding siteof the leg restriction means 82 is bigger than the bonding site of theleg restriction means 80. Therefore, the leg restriction means 80 iscapable of withstanding the applied extension force higher than thewaist restriction means 80. As shown in FIG. 10, the leg side ofstretchable panel 46 follows a path indicated by the arrow P and thewaist side of the stretchable panel 46 follows a path indicated by thearrow Q. Alternatively, the bonding site of the waist restriction meansmay be bigger than the bonding site of the leg restriction means suchthat the waist restriction means is capable of withstanding the appliedextension force higher than the leg restriction means.

[0042]FIG. 11 shows an alternative embodiment of a stretchable fasteningmember 40. The stretchable fastening member 40 shown in FIG. 11comprises a plurality of restriction means 90 disposed generally in thelongitudinal direction. The stretchable panel 46 comprises a firststretchable zone 92 and a second stretchable zone 94. The restrictionmeans 90 virtually divides the stretchable panel 46 into the firststretchable zone 92 and the second stretchable zone 94 at a lineconnecting a plurality of restriction means 90. In FIG. 11, eachrestriction means is disposed such that each longitudinal intervalbetween the adjacent restriction means is different. In the embodimentin shown in FIG. 11, the interval is smaller at the waist side of thestretchable panel 46 than at the leg side of the stretchable panel 46.Alternatively, the interval may be bigger at the waist side of thestretchable panel 46 than at the leg side of the stretchable panel 46FIG. 12 shows an alternative embodiment of a stretchable fasteningmember 40. The stretchable fastening member 40 shown in FIG. 12comprises three restriction means 100 such that a line connecting thethree restriction means 100 are disposed at an angle with thelongitudinal direction. The stretchable panel 46 comprises a firststretchable zone 102 and a second stretchable zone 104. The restrictionmeans 100 virtually divides the stretchable panel 46 into the firststretchable zone 102 and the second stretchable zone 104 at a lineconnecting the three restriction means 100. If necessary, additionalrestriction means 106 may be added in the second stretchable zone 102.

[0043]FIG. 13 shows an alternative embodiment of a stretchable fasteningmember 40. The stretchable fastening member 40 shown in FIG. 13comprises a restriction means 110 having a line shape. In theembodiment, the line shape restriction means 110 is disposed in thelongitudinal direction. The stretchable panel 46 comprises a firststretchable zone 112 and a second stretchable zone 114. The restrictionmeans 110 virtually divides the stretchable panel 46 into the firststretchable zone 112 and the second stretchable zone 114 at a lineconnecting the two restriction means 110. The restriction means 110 maycomprise two or more line shape restriction means divided in thelongitudinal direction.

What is claimed is:
 1. An absorbent article comprising a chassis and astretchable fastening member, the chassis extending longitudinally andlaterally and comprising a liquid pervious topsheet, a liquid imperviousbacksheet and an absorbent core disposed therebetween, the stretchablefastening member comprising a fixed portion permanently joined to thechassis, a distal portion provided with a fastening material and astretchable panel positioned between the fixed portion and the distalportion, the stretchable fastening member being joined to the chassissuch that the distal portion is positioned laterally outwardly from thefixed portion in the flat-out configuration of the stretchable fasteningmember, wherein the stretchable panel of the stretchable fasteningmember comprises a first stretchable zone and a second stretchable zonedisposed in the lateral direction, the first stretchable zone is capableof providing extensibility upon an initially applied extension force,and extensibility of the second stretchable zone is restricted by arestriction means until the restriction means is inactivated, and therestriction means is inactivated upon a further applied extension forcesuch that the second stretchable zone provides an additionalextensibility to reduce a stress developed in the stretchable panel. 2.The absorbent article of claim 1 wherein the restriction means isinactivated upon the applied extension force being not more than 350g/25 mm.
 3. The absorbent article of claim 1 wherein the chassiscomprises a side flap being less stretchable than the stretchable panel,and at least a portion of the stretchable panel is superposed on theside flap of the chassis wherein, the restriction means comprises abonding means to detachably join a portion of the stretchable panel tothe side flap of the chassis between the fixed portion and the distalportion to provide the first stretchable zone extending between thedistal portion and the bonding means and the second stretchable zoneextending between the fixed portion and the bonding means.
 4. Theabsorbent article of claim 3 wherein the bonding means is provided inthe configuration where the stretchable panel is unfolded.
 5. Theabsorbent article of claim 3 wherein the side flap of the chassis isnon-stretchable.
 6. The absorbent article of claim 3 wherein the bondingmeans is detached upon the applied extension force being not more than350 g/25 mm.
 7. The absorbent article of claim 3 wherein the bondingmeans comprises a waist bonding means and a leg bonding means.
 8. Theabsorbent article of claim 7 wherein the bonding strength of the waistbonding means is different from the bonding strength of the leg bondingmeans.